EP3432429B1 - Composite electrode for low-voltage surge arrester with multiple spark gaps in series - Google Patents

Description

The present invention provides a new configuration for surge arresters with multiple spark gaps in series with compound electrodes. Each spark gap stage consists of a main electrode (4) in non-metallic conductor or alloy, an auxiliary electrode (1) in metallic conductor, and a flexible separating insulator (3), which withstands a very high temperature . The last stage is closed by a main closing electrode (6). The auxiliary electrode (1) is placed in contact with the main electrode (4) by embedding on one side and is followed by the separation insulator (3) on the other side. The main electrodes (4), auxiliary (1), and the insulators (3) of all the stacked spark gaps are arranged between the two clamping plates (2) which are then locked by clips (5).

This invention gives a new shape to the main electrode (4) made of non-metallic material or alloy. It is flat on one surface, and has a slightly hollow edge (9) on the other surface. It may be in the form of ⊏, or C or U, or -, or I, or in circular, or hollow circular, or polygonal, or hollow polygonal form. The main closing electrode (6) retains the same shape as the main electrodes but does not have a hollow edge.

The invention introduces an auxiliary electrode (1) in metallic conductor. Said auxiliary electrode (1) may also be in the form of ⊏, or C or U, or -, or I, or in circular, or hollow circular, or polygonal, or hollow polygonal shape depending on the shape of the main electrode to fit into it. It is therefore placed and clamped between a main electrode (4) and a separation insulator (3). Said metallic conductor electrode comprises the part in contact with the main electrode (7) and a connected connection tab (8) for the connection with a high voltage trigger circuit.

The underlined shapes are also applied for the separation insulation (3).

• Un très fort pouvoir d'écoulement, 10 chocs de 25kA en onde 10/350µs et 120kA en 8/20µs
• Un faible niveau de Protection (<1,5kV) qui permet une bonne protection de la plupart des équipements électroniques.
• Une tension de service élevée (Uc peut atteindre 500 V en AC)
• Un ratio Up/Un < 3
  Up : niveau de protection ; Un : tension de service
• Une grande capacité d'extinction du courant de suite>6kA sous 385Vac
• Faible volume 65mm^∗90mm^∗18mm

This new configuration creates a new low voltage surge arrester. Here are the characteristics that distinguish it for a modular surge arrester in standard size 18mm thick:

• Very high flow power, 10 shocks of 25kA in 10 / 350µs wave and 120kA in 8 / 20µs
• A low level of Protection (<1.5kV) which allows good protection of most electronic equipment.
• A high operating voltage (Uc can reach 500 V in AC)
• An Up / Un ratio <3
  Up: level of protection; A: operating voltage
• A high extinguishing capacity of the following current> 6kA at 385Vac
• Low volume 65mm ^∗ 90mm ^∗ 18mm

Technical area

The present invention low voltage surge arresters (<1500v) intended for protection against atmospheric and industrial overvoltages. It provides a new configuration for multi-spark arresters in series with compound electrodes.

Context

1. 1) L'électrode de déclenchement n'est pas stable. Elle se compose simplement d'un point de contact mécanique d'une aiguille avec l'électrode graphite à l'extérieur de l'éclateur de décharge. Au moment de la décharge du courant impulsif, il y a une vibration due à la force électromagnétique et cela entraîne des coupures de contact. De plus, à la suite du courant de décharge répétitif, les points de contact entre les aiguilles de de déclenchement et les électrodes graphites sont oxydés, ou détériorés par les casses des électrodes graphite. Le déclenchement d'amorçage des éclateurs de décharge ne fonctionnera alors plus : soit à cause de la coupure de contact, soit à cause du mauvais contact.
2. 2) La tension d'amorçage élevée U amorçage sous l'onde 1.2/50µs > 2kV et ainsi son niveau de protection élevé (Up=Uc) à cause d'un manque de déclenchement à l'intérieur de l'éclateur graphite au début de l'onde impulsionnelle.

There are currently low voltage surge arresters made up of multiple spark gaps in graphite electrode. These surge arresters have strong flow powers in 10 / 350µs and 8 / 200µs waves, high temperature resistance by the graphite material and low economic cost ( EP 2 615 703 A2 (DEHN & SOEHNE [DE]); WO 2017/080825 A1 (DEHN + SÖHNE GMBH + CO KG [DE])). However, these surge arresters have two major flaws. Here they are below:

1. 1) The trigger electrode is not stable. It simply consists of a point of mechanical contact of a needle with the graphite electrode outside the discharge spark gap. At the moment of discharging the impulsive current, there is a vibration due to the electromagnetic force and this leads to contact cuts. In addition, as a result of the repetitive discharge current, the contact points between the trigger needles and the graphite electrodes are oxidized, or deteriorated by the breakage of the graphite electrodes. The triggering of the discharge spark gaps will then no longer function: either because of the contact cut-off, or because of the bad contact.
2. 2) The high starting voltage U starting under the wave 1.2 / 50µs> 2kV and thus its high level of protection (Up = Uc) due to a lack of tripping inside the graphite spark gap at the start of the pulse wave.

These existing surge arresters have another characteristic which can be qualified as a weak point. At the extinction level, the surge arrester is able to cut the current immediately once started under the service voltage but the number of graphite spark gaps is too large for such a service voltage, which is undesirable for miniaturization lightning arresters.

To remedy this flaw, the present invention introduces a metallic conductor electrode following the main electrode (4) of each spark gap stage. This auxiliary electrode (1) in metallic conductor allows both the ignition of the ignition inside the spark gaps at the start of the pulse waves, as well as a low level of protection, and a reinforcement of the extinction of the gas. electric arc thanks to its heat dissipation during the arc. This provides a very strong power to cut the current. Its location between the main electrodes (4) clamped and separated by a flexible insulator (3) allows a long life of the shock current withstand and vibration free at the time of discharge due to electromagnetic force.

Disclosure of the invention

The present invention is obtained by a compound electrode according to claim 1 and by a surge arrester according to claim 4. The arrester consists of spark gaps stacked in series with compound electrodes. Each spark gap stage consists of a main electrode (4) in non-metallic conductor or alloy, an auxiliary electrode (1) in metallic conductor, and a flexible separation insulator (3), which withstands a very high temperature. . On one side of a main electrode (4), there is a hollow space (9) at the edge thereof, the auxiliary electrode (1) is embedded inside this hollow. The two electrodes are in electrical contact. The number of spark gap stages is determined by the operating voltage. The last stage is closed by a main closing electrode (6). The main electrodes (4), the auxiliary electrodes (1) and the insulators (3) are arranged between the two clamping plates (2) which are then locked by the clips (5). This tightening method supplemented by the surface contact makes it possible to ensure the good contact of the two electrodes, as well as the correct operation of the triggering and to minimize the spark gap ignition voltage. The legs (8) of the auxiliary electrodes (1) in metallic conductor are placed in the same direction for connection with a high voltage trigger circuit.

Said main electrode (4) in non-metallic conductor or alloy can be represented either in the form of ⊏, or C or U, or -, or I, or in circular, or hollow circular, or polygonal, or hollow polygonal. It is flat on one surface, and has a slightly hollow edge (9) on the other surface. The main closing electrode (6) retains the same shape as the main electrodes but does not have a hollow edge.

Said electrode in auxiliary conductor (1) in metallic conductor may be represented either in the form of ⊏, or C or U, or -, or I, or in circular, or hollow circular, or polygonal, or hollow polygonal form depending on the shape of the main electrode to fit into it. It comprises the part in contact (7) "with the main electrode (4) and a connection tab (11) for the connection with a high voltage trigger circuit.

Said flexible separating insulator (3) can be represented either in the form of ⊏, or C or U, or -, or I, or in circular, or hollow circular, or polygonal, or hollow polygonal form.

Said main electrode (4) in non-metallic conductor or alloy is arranged on a flat surface and on the other side a recessed part (9) at the electrode edge level.

The auxiliary electrode (1) fits into the part of the main electrode (4) hollow (9) and thus comes into electrical contact on the surface therewith.

Said metallic conductor auxiliary electrode (1) is made of a metallic material having electrically conductive properties.

DESCRIPTION OF FIGURES

• The figure 1 is a schematic drawing of current technology on the market;
• The figures 2 are schematic drawings of one embodiment of the invention;
  • The figure 2-a corresponds to a drawing of multiple spark gaps stacked in series with a main closing electrode (6);
  • The figure 2-b corresponds to a drawing of the clamping plates (2) and of the clips (5) which fix the multiple spark gaps;
  • The figure 2-c corresponds to a drawing of the multiple spark gaps fixed between the clamping plates (2) and fasteners (5);
• The figure 3 is a schematic drawing of the auxiliary electrode (1) in ⊏-shaped metallic conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 4 is a schematic drawing of the auxiliary electrode (1) in the shape of a - metal conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 5 is a schematic drawing of the auxiliary electrode (1) in rectangular shaped metallic conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 6 is a schematic drawing of the auxiliary electrode (1) in metallic conductor in square shape. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 7 is a schematic drawing of the auxiliary electrode (1) made of an elliptical metallic conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 8 is a schematic drawing of the auxiliary electrode (1) made of a triangular-shaped metallic conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 9 is a schematic drawing of the auxiliary electrode (1) made of metal conductor in hexagonal shape. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 10 is a schematic drawing of the auxiliary electrode (1) made of a circular metal conductor. It comprises a part in contact with the main electrode (7) and a connection tab (8);
• The figure 11 is a schematic drawing of a main electrode (4) in non-metallic conductor or alloy provided with a hollow part (9);
• The figure 12 is a schematic drawing of a main electrode (6) in non-metallic conductor or alloy without a hollow part for closing the last stage of multiple spark gaps.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

The utility model is described in more detail with reference to the following example.

• Fig. 2-a : électrode auxiliaire (1) en conducteur métallique avec patte conductrice
• Fig. 2-a : isolant souple de séparation (3)
• Fig. 2-a : électrode principale (4) en conducteur non-métallique ou alliage, disposée d'une face plate et d'autre face une partie en creux (9)
• Fig.2-a : électrode principale de fermeture (6) en conducteur non-métallique ou alliage sans partie creuse
• Fig. 2-b : plaques de serrage (2)
• Fig. 2-b : attache (5)
• Fig. 2-c : électrode auxiliaire (1) en conducteur métallique avec patte
• Fig. 2-c : isolant souple de séparation (3)
• Fig. 2-c : électrode principale (4) en conducteur non-métallique ou alliage, disposée d'une face plate et d'autre face une partie en creux (9)
• Fig. 2-c : électrode principale de fermeture (6) en conducteur non-métallique ou alliage sans partie creuse

The structure of a multi-spark arrester in series with compound electrodes is shown in the figures 2 .

• Fig. 2-a : auxiliary electrode (1) in metallic conductor with conductive tab
• Fig. 2-a : flexible separation insulation (3)
• Fig. 2-a : main electrode (4) in non-metallic conductor or alloy, arranged on one flat side and on the other side a hollow part (9)
• Fig. 2-a : main closing electrode (6) in non-metallic conductor or alloy without hollow part
• Fig. 2-b : clamping plates (2)
• Fig. 2-b : tie (5)
• Fig. 2-c : auxiliary electrode (1) in metallic conductor with bracket
• Fig. 2-c : flexible separation insulation (3)
• Fig. 2-c : main electrode (4) in non-metallic conductor or alloy, arranged on one flat side and on the other side a hollow part (9)
• Fig. 2-c : main closing electrode (6) in non-metallic conductor or alloy without hollow part

• Fig. 3 à 10 : partie en contact avec l'électrode principale (7)
• Fig. 3 à 10 : patte de connexion (8)

The auxiliary electrode (1) in metallic conductor with connection tab is shown on the figures 3 to 10 .

• Fig. 3 to 10 : part in contact with the main electrode (7)
• Fig. 3 to 10 : connection tab (8)

• Fig. 11 : électrode principale (4) en conducteur non-métallique ou alliage, disposée d'une face plate et d'autre face une partie en creux (9)
• Fig. 12 : électrode principale de fermeture (6) en conducteur non-métallique ou alliage sans partie creuse

The main electrode (4) in non-metallic conductor or alloy is shown on the figures 11 and 12 .

• Fig. 11 : main electrode (4) in non-metallic conductor or alloy, arranged on one flat side and on the other side a hollow part (9)
• Fig. 12 : main closing electrode (6) in non-metallic conductor or alloy without hollow part

The basic principles, main features and advantages of the utility model have been demonstrated and described above. Those skilled in the art should understand that the present invention is not limited to the example cited above. This and the description of the sheet merely illustrate the principles of the present invention. The characteristics and advantages of the invention described above are given only by way of nonlimiting example and do not limit the invention which is defined by the claims.

Claims (6)

1. Composite electrode for low-voltage surge arrester with multiple spark gaps in series, the composite electrode comprising a main electrode (4) made of a non-metallic or alloy conducting material and an auxiliary electrode (1) made of a metallic conducting material, characterised in that the auxiliary electrode (1) is embedded in a hollow space (9) of the main electrode (4) and is in electrical contact on one side with a surface of the main electrode (4), the auxiliary electrode being configured to come into contact on the other side with a flexible separation insulator (3) to form a spark gap, the auxiliary electrode (1) comprising the part in contact (7) with the main electrode (4) and a connection lug (8) for the link with a high-voltage triggering circuit.
2. Composite electrode according to claim 1 for low-voltage surge arrester with multiple spark gaps in series, characterised in that its main electrode (4) made of a non-metallic or alloy conducting material has a ⊏, or C or U, or -, or I shape, or a circular, or hollow circular, or polygonal, or hollow polygonal shape.
3. Composite electrode according to claim 1 for low-voltage surge arrester with multiple spark gaps in series, characterised in that its auxiliary electrode (1) made of a metallic conducting material, composed of a metallic material having conducting properties, is flat and whose part in contact with the main electrode (7) has a ⊏, or C or U, or -, or I shape, or a circular, or hollow circular, or polygonal, or hollow polygonal shape, and is provided with a connection lug (8) for the link with a high-voltage triggering circuit.
4. Low-voltage surge arrester with multiple spark gaps in series comprising several composite electrodes stacked in series according to claim 1, and further comprising

   - for each composite electrode, a flexible separation insulator (3) physically and electrically separating said composite electrode of the main electrode (4) from the adjacent composite electrode thus forming a spark gap;

   - a main closure electrode (6) arranged above the stack of composite electrodes;

   - two clamping plates (2) clamping the composite electrodes and the closure electrodes (6) together, and;

   - fasteners (5) locking the clamping plates (2), the lugs (8) of the auxiliary electrodes (1) of the composite electrodes pointing in the same direction.
5. Low-voltage surge arrester with multiple spark gaps in series comprising several composite electrodes stacked in series according to claim 4, characterised in that the main electrodes (4) made of a non-metallic or alloy conducting material composed of a flat surface and other surface comprising a hollow part (9) on the edge of the electrode allowing the auxiliary electrode (1) to come into contact with the main electrode (4) by embedment and the clamping mode complemented by the surface contact ensure good contact between the two electrodes and correct operation of the triggering, i.e. triggering of the arcing inside the spark gaps.
6. Low-voltage surge arrester with multiple spark gaps in series comprising several composite electrodes stacked in series according to claim 4, characterised in that the flexible separation insulators (3) withstand a very high temperature and have a ⊏, or C or U, or -, or I shape, or a circular, or hollow circular, or polygonal, or hollow polygonal shape.

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